Known intrusion detection systems can include door and window contact systems and methods that are based on reed and magnet technology. While inexpensive to implement, reed and magnet technology presents at least three significant limitations.
First, in reed and magnet technology, there are limitations on the distance of the gap between the electrical contacts of the reed switch. “Wide-gap” reed switches have had their maximum functional gap stretched to reliable limits through various methods. However, mounting the electrical contacts of the reed switch on surfaces constructed of ferrous metal materials can result in a magnetic flux field interference that reduces the maximum operating gap. To maximize the effective gap, an expensive magnet is required, which is undesirable.
Second, reed and magnet technology is vulnerable to attempts to defeat (AtD) the system by an intruder. For example, the electrical contacts in the reed switch can be defeated by an intruder introducing a magnet in close proximity to the reed. Some systems and methods are known to reduce such security vulnerability, but all incur additional cost, which is undesirable.
Furthermore, in some situations, a user may wish to arm the system while a window(s) is in a partially opened position. However, such a position will likely exceed the maximum functional gap of the electrical contacts of the reed switch. Accordingly, a “bypass” mode can be invoked, but the “bypass” mode can further compromise perimeter intrusion detection, thereby making attempts to defeat by an intruder more likely to be successful.
Finally, when reed and magnet technology is employed, a magnet must be installed in the system. Such an installation further adds to overall cost.
In view of the above, there is a continuing, ongoing need for a system and method to address the gap, security, and robustness limitations of known door and window contact systems and methods without increasing the overall cost thereof.